The drug Zolpidem. Has a sedative (sleep-inducing) effect when taken. Used by Air Force operators to help them calm down after taking stimulants to stay awake during long missions. The opposite of a go-pill.

Also used before a mission to calm nerves and promote sleep.

After flying for 120 hours nonstop, having taken many go-pills in the process, the pilots required a no-go pill to help them sleep.